feat(11-01): UIE-02 — dedicated Add Printer page at GET /printers/new

- Create imptune/templates/printers_new.html: full page extending base.html
  with plain <form action="/printers" method="post"> (no HTMX, browser follows 303)
  and inline driver upload sub-form
- Update imptune/templates/printers.html: remove inline Add Printer form,
  add <a href="/printers/new" role="button">Add Printer</a> link
- Add GET /printers/new route in imptune/api/pages.py (placed before /{printer_id})
- Change POST /printers to always return RedirectResponse(url='/printers', status_code=303)
- Update existing POST /printers tests to assert 303 + follow_redirects=False
- Update test_printer_form.py to check /printers/new instead of /printers (UIE-02 arch)
- UIE-02 tests GREEN; UIE-01/03 scaffolds remain RED (expected — not yet implemented)

imptune/templates/printers_new.html

@@ -0,0 +1,100 @@
+{% extends "base.html" %}
+
+{% block content %}
+<h1>Add Printer</h1>
+
+<p><a href="/printers">&larr; Back to Printer Library</a></p>
+
+<div x-data="{ ip: '', port: '', portEdited: false }">
+  <form action="/printers" method="post">
+
+    <label>
+      Printer Name
+      <input type="text" name="name" placeholder="e.g. HP LaserJet 4050" required>
+    </label>
+
+    <label>
+      IP Address
+      <input type="text" name="ip_address"
+             x-model="ip"
+             @input="if (!portEdited) port = 'IP_' + ip.replaceAll('.', '_')"
+             placeholder="e.g. 192.168.1.100"
+             required>
+    </label>
+
+    <label>
+      Port Name
+      <input type="text" name="port_name"
+             x-model="port"
+             @change="portEdited = true"
+             @keydown="portEdited = true"
+             placeholder="e.g. IP_192_168_1_100">
+    </label>
+
+    <label>
+      Driver
+      <select name="driver_id" id="printer-form-driver-select">
+        <option value="">-- No driver --</option>
+        {% for item in driver_data %}
+        <option value="{{ item.driver.id }}">
+          {{ item.driver.original_filename }} ({{ item.names | join(', ') }})
+        </option>
+        {% endfor %}
+      </select>
+    </label>
+
+    <label>
+      Duplex Mode
+      <select name="duplex_mode">
+        <option value="OneSided" selected>One-Sided</option>
+        <option value="LongEdge">Long Edge</option>
+        <option value="ShortEdge">Short Edge</option>
+      </select>
+    </label>
+
+    <label>
+      <input type="checkbox" name="color_mode" value="on" checked>
+      Color Mode
+    </label>
+
+    <label>
+      Paper Size
+      <select name="paper_size">
+        <option value="A4" selected>A4</option>
+        <option value="Letter">Letter</option>
+        <option value="Legal">Legal</option>
+      </select>
+    </label>
+
+    <label>
+      <input type="checkbox" name="collate" value="on" checked>
+      Collate
+    </label>
+
+    <label>
+      Client
+      <select name="client_id">
+        <option value="">-- Unassigned --</option>
+        {% for c in clients %}
+        <option value="{{ c.id }}">{{ c.name }}</option>
+        {% endfor %}
+      </select>
+    </label>
+
+    <button type="submit">Save Printer</button>
+  </form>
+
+  <form hx-post="/drivers/upload"
+        hx-target="#driver-list"
+        hx-encoding="multipart/form-data"
+        hx-swap="outerHTML">
+    <input type="hidden" name="caller" value="printer_form">
+    <label>
+      Upload New Driver
+      <input type="file" name="file" accept=".zip" required>
+    </label>
+    <button type="submit" class="secondary">Upload Driver</button>
+  </form>
+  <div id="driver-list" style="display:none"></div>
+</div>
+{% endblock %}